Vehicle cooling system

ABSTRACT

An integrated cooling system having two separate evaporator coils is provided. Each evaporator coil has its own shutoff, thereby allowing for individual control over the cooling of each of two vehicle spaces. The evaporator coils may be disposed within the vehicle to cool the passenger compartment and a battery compartment, respectively. The separate control afforded by the cooling system provides the flexibility of shutting off cooling to the vehicle passenger compartment for the comfort of the vehicle occupants, while still providing cooling to the battery, as needed. The cooling system includes a number of control features which provide for automatically shutting off cooling to one or more of the evaporator coils based on parameters such as air temperature and refrigerant pressure.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a vehicle cooling system, and moreparticularly, a system for separately cooling more than one vehiclespace.

2. Background Art

There are a variety of vehicles today which utilize electricity, and inparticular an electric motor, to at least assist in powering thevehicle. For example, there are electric vehicles, which are poweredexclusively by an electric motor; hybrid electric vehicles (HEV), whichmay be selectively powered by an internal combustion engine or anelectric motor; and fuel cell vehicles, or hybrid fuel cell vehicles,just to name a few. The electric motor used in such vehicles may have anelectrical power source such as a fuel cell or a battery.

In the case of a battery used to provide power to an electric motor todrive a vehicle, the temperature of the battery can increasesignificantly when the motor is used for extended periods of time. Theincrease in battery temperature may be compounded when the battery isconfined to a relatively small, enclosed space. If the increase inbattery temperature is left unchecked, the battery life may be reduced.Thus, it is desirable to provide a system for cooling a battery, orbatteries, in a vehicle to keep the battery temperature low enough thatthe battery life is not reduced.

In addition to the added requirement of keeping the battery cool in ahybrid electric vehicle, there is also a need to provide a coolingsystem for the vehicle passenger compartment, just as in a conventionalvehicle. Although separate systems may be used to provide cool air tothe battery and the vehicle passenger compartment, an integrated, or atleast partially integrated, cooling system can be used. One attempt toprovide an integrated cooling system for both a battery and a vehiclepassenger compartment, is described in U.S. Pat. No. 6,138,466 issued toLake et al. on Oct. 31, 2000.

Lake et al. discusses the use of a cooling system having an inside heatexchanger for adjusting the temperature of air flowing into thepassenger compartment, and a zone-control heat exchanger which may beused for cooling a battery assembly. Lake et al. does not describe amechanism for detecting the temperature of the air at each heatexchanger, and automatically stopping the flow of cooling fluid to aheat exchanger when the detected temperature falls below a predeterminedtemperature. Lake et al. does describe disabling operation of the insideheat exchanger when the ambient air temperature outside the vehicle islow, but this does not account for local temperatures near the heatexchanger, nor does it protect the zone-control heat exchanger fromicing. In addition, Lake et al. does not describe a mechanism forproviding fresh air directly across the battery. This may lead tounnecessary energy consumption, when the temperature of the ambient airoutside the vehicle is low enough to cool the battery without the use ofa heat exchanger.

Thus, a need still exists for a vehicle cooling system that at leastpartially integrates passenger compartment cooling and vehicle batterycooling, and includes a mechanism for automatically shutting off theflow of coolant to an individual heat exchanger when the temperature ofthat heat exchanger becomes too low, thereby helping to prevent icing onthe heat exchanger. In addition, there exists a need for a vehiclecooling system that at least partially integrates passenger compartmentcooling and vehicle battery cooling, and provides a fresh air intakedirectly connected to the vehicle battery, so that at least a portion ofthe vehicle cooling system can be shut down when the temperature of theambient air outside the vehicle is low enough to adequately cool thebattery without the use of the cooling system.

SUMMARY OF INVENTION

Therefore, a cooling system for a vehicle having first and second spacesto be cooled is provided. The cooling system includes first and secondheat exchangers for respectively cooling air flowing into the first andsecond vehicle spaces. A conduit system is in communication with thefirst and second heat exchangers, and is configured to provide a fluidflow path to and from the heat exchangers. A pump is selectivelyoperable for moving fluid through the conduit system, and first andsecond valves are in communication with the conduit system. A firstsensor is configured to measure a first temperature, and to output asignal related to the first temperature. The first temperature isindicative of the temperature of air exiting the first heat exchanger. Asecond sensor is configured to measure a second temperature, and tooutput a signal related to the second temperature. The secondtemperature is indicative of the temperature of air exiting the secondheat exchanger. A controller is in communication with the first andsecond sensors, and with at least one of the pump and the first andsecond valves. The controller is configured to effect a stoppage offluid flow to the first heat exchanger when the first temperature isbelow a predetermined temperature. The controller is also configured toeffect a stoppage of fluid flow to the second heat exchanger when thesecond temperature is below the predetermined temperature.

The invention also provides a cooling system as described above, furtherincluding a duct system having at least a portion of the second heatexchanger disposed therein. The duct system is configured to selectivelyprovide fluid communication between a battery and an ambient environmentoutside the vehicle.

The invention further provides a cooling system for a vehicle havingfirst and second spaces to be cooled. The cooling system includes firstand second heat exchangers for respectively cooling air flowing into thefirst and second vehicle spaces. A conduit system is in communicationwith the first and second heat exchangers, and is configured to providea fluid flow path to and from the heat exchangers. A pump is selectivelyoperable for moving fluid through the conduit system; the pump includesan inlet and an outlet. First and second valves are in communicationwith the conduit system. A switch is disposed between one of the heatexchangers and the pump inlet. The switch is configured to determine afluid pressure in the conduit system, and to effect shutdown of the pumpwhen the determined fluid pressure is below a predetermined pressure.

The invention also provides a vehicle having a passenger compartment anda battery. The vehicle includes a cooling system having first and secondheat exchangers. The first heat exchanger is disposed in relation to thepassenger compartment for selectively cooling air flowing into thepassenger compartment. The second heat exchanger is disposed in relationto the battery for selectively cooling air flowing across the battery. Aconduit system is in communication with the first and second heatexchangers, and is configured to provide a fluid flow path to and fromthe heat exchangers. First and second valves communicate with theconduit system. The first valve is configured to selectively inhibitfluid flow to the first heat exchanger. The second valve is configuredto selectively inhibit fluid flow to the second heat exchanger. Thecooling system also has first and second sensors. The first sensor isconfigured to measure a first temperature indicative of the temperatureof air exiting of the first heat exchanger; the first sensor is alsoconfigured to output a signal related to the first temperature. Thesecond sensor is configured to measure a second temperature indicativeof the temperature of air exiting the second heat exchanger, and isfurther configured to output a signal related to the second temperature.A controller is in communication with the first and second sensors, andat least one of the pump and the first and second valves. The controlleris configured to effect a stoppage of fluid to the first heat exchangerwhen the first temperature is below a predetermined temperature. Thecontroller is further configured to effect a stoppage of fluid flow tothe second heat exchanger when the second temperature is below thepredetermined temperature.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic representation of a cooling system in accordancewith the present invention;

FIG. 2 is a graphical illustration of the zones of operation of acooling system that does not have a separate shutoff valve for each oftwo evaporator coils;

FIG. 3 is a graphical illustration of the zones of operation of acooling system in accordance with the present invention;

FIG. 4 is a partial fragmentary perspective view of a portion of thecooling system shown in FIG. 1; and

FIG. 5 is a perspective view of a portion of a vehicle and a portion ofthe cooling system shown in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a cooling system 10 for a vehicle having a first space tobe cooled, such as a passenger compartment 12, and a second space to becooled, such as a battery compartment 14. Inside the battery compartment14 is a traction battery 16 used to power a motor (not shown) used topropel the vehicle. Of course, a cooling system, such as the coolingsystem 10, can be used to cool vehicle spaces other than a passengercompartment and a battery compartment.

The cooling system 10 includes a first heat exchanger, or frontevaporator coil 18, which is disposed in relation to the passengercompartment 12 for selectively cooling the air flowing into thepassenger compartment 12. The cooling system 10 also includes a secondheat exchanger, or rear evaporator coil 20. The rear evaporator coil 20is disposed in relation to the battery compartment 14 for selectivelycooling the air flowing into the battery compartment 14 and across thebattery 16. A first fan 22 cooperates with a front duct system 24 formoving air through the front evaporator coil 18 and into the passengercompartment 12. A second fan 26 cooperates with a rear duct system 28for moving air through the rear evaporator coil 20, into the batterycompartment 14, and across the battery 16. As seen in FIG. 1, the rearevaporator coil 20 is disposed within the rear duct system 28.

A conduit system 30 is in communication with the front and rearevaporator coils 18, 20, and is configured to provide a fluid flow pathto and from the evaporator coils 18, 20. In particular, a pump, orcompressor 32, is selectively operable to move a fluid such as arefrigerant through the conduit system 30. The compressor 32 includes aninlet 34 and an outlet 36.

A first valve 38 communicates with the conduit system 30, and isconfigured to selectively inhibit the flow of refrigerant through thefront evaporator coil 18. Similarly, a second valve 40 communicates withthe conduit system 30, and is configured to selectively inhibit the flowof refrigerant to the rear evaporator coil 20. Because separate valves38, 40 are used to control the flow of refrigerant to the front and rearevaporator coils 18, 20, the cooling system 10 can be used to providecooling to a single vehicle space. That is, if cooling is desired in thepassenger compartment only, the second valve 40 can be closed such thatrefrigerant does not flow through the rear evaporator coil 20.Similarly, if the battery 16 needs to be cooled, but the passengercompartment 12 does not, the first valve 38 can be closed, such thatrefrigerant flows through only the rear evaporator coil 20.

Providing separate valves 38, 40 for the front and rear evaporator coils18, 20 provides an improvement over vehicle cooling systems that do nothave separate shutoff valves for each evaporator coil. Without aseparate shutoff valve for each evaporator coil, refrigerant will flowthrough both evaporator coils even if only one of the two vehicle spacesis calling for cooling. This may lead to undesirably cool air flowinginto the vehicle space that did not request cooling.

FIGS. 2 and 3 graphically illustrate an advantage of having separateshutoff valves, such as the valves 38, 40 in the cooling system 10. Whenseparate evaporator coils are used in a single cooling system, there arefour possible zones of operation: 1) both the front and rear evaporatorcoils are on; 2) the front evaporator coil is on, but the rearevaporator coil is off; 3) both the front and rear evaporator coils areoff; and 4) the front evaporator coil is off, but the rear evaporatorcoil is on.

FIG. 2 illustrates the situation found in vehicles having a coolingsystem with front and rear evaporator coils which respectively coolfront and rear portions of a large passenger compartment. In such asystem, where a separate shutoff valve is not provided for the frontevaporator coil, priority is given to the front passengers. In zones 1and 3, the front and rear passengers are presumably in agreement, sinceboth evaporator coils are either on or off. In zones 2 and 4, however,the rear passengers have different demands.

For example, FIG. 2 shows that the rear evaporator coil is off in zone2; nonetheless, refrigerant will continue to flow through the coilbecause the front evaporator coil is calling for cooling. Thus, the rearpassengers may experience undesirably cool air which results from thelack of a separate shutoff valve to stop the flow of refrigerant to therear evaporator coil. Similarly, in zone 4 the front evaporator coil isoff, which stops the flow of refrigerant through the entire system.Therefore, even though the rear evaporator coil is on, and the rearpassengers may desire cool air, no refrigerant flows through the rearevaporator coil. This is not the case for a cooling system, such as thecooling system 10, which is operational in all four zones, since eachevaporator coil has its own shutoff valve—see FIG. 3. Thus, the batterycompartment 14 can continued to receive cool air even when the passengercompartment 12 does not.

Returning to FIG. 1, it is seen that the cooling system 10 includes afirst sensor, or thermistor 42, which is configured to measure thetemperature of the air exiting the front evaporator coil 18, and tooutput a signal related to the measured temperature. A second sensor, orthermistor 44, is configured to measure the temperature of the airexiting the rear evaporator coil 20, and to output a signal related tothe measured temperature. A controller, or powertrain control module(PCM) 46, is in communication with various components of the coolingsystem 10. For example, the PCM 46 is capable of controlling thecompressor 32 to start and stop the flow of refrigerant through theconduit system 30.

The compressor 32 includes an on/off clutch for starting and stoppingthe flow of refrigerant through the conduit system 30. Of course, othertypes of compressors may be used, for example, a variable displacementcompressor without a clutch. Such a compressor would control the flow offluid through the conduit system 30 by modulating the displacement ofthe compressor, as needed. Alternatively, a high voltage, integratedelectric motor driven compressor could be used.

The PCM 46 is in communication with the thermistors 42, 44 to receivesignals related to their respective measured air temperatures. The PCM46 also communicates with the valves 38, 40, such that the PCM 46 caneffect a stoppage of refrigerant flow to either evaporator coil 18, 20by closing the appropriate valve 38, 40. Although the PCM 46 is shown inFIG. 1 as a single controller communicating directly with variouselements of the cooling system 10, other controller configurations mayalso be used. For example, individual elements of the cooling system 10such as the compressor 32 and the valves 38, 40 may have individualcontrollers, each of which would then be connected to a centralcontroller, such as the PCM 46.

The cooling system 10 also includes a third heat exchanger, or condenser48, which communicates with the conduit system 30, and is disposedbetween the pump outlet 36 and the front and rear evaporator coils 18,20. The condenser 48 receives hot, high-pressure vapor refrigerant fromthe compressor 32. Fans 50, 52 move air across the condenser 48 to cooland condense the refrigerant as it moves from condenser inlet 54 tocondenser outlet 56.

The cooling system 10 also includes a first throttling device, ororifice tube 58, and a second throttling device, or thermal expansionvalve (TXV) 60. The orifice tube 58 and the TXV 60 each communicate withthe conduit system 30, and are configured to effect a reduction inpressure of the refrigerant before it reaches the front and rearevaporator coils 18, 20, respectively. A cooling system, such as thecooling system 10, may have a different configuration of throttlingdevices—e.g., two orifice tubes or two TXVs.

A number of considerations may be important when choosing the type ofthrottling device to use with a cooling system, such as the coolingsystem 10. For example, a TXV may be more expensive than an orificetube; however, use of an orifice tube may require a reservoir, such asan accumulator 62, which requires additional space. The accumulator 62communicates with the conduit system 30, and is configured totemporarily store at least some of the refrigerant flowing in theconduit system 30. The accumulator 32 separates the liquid refrigerantfrom the liquid and vapor mixture exiting the front evaporator coil 18.This helps to ensure that most of the refrigerant reaches the compressor32 in a gaseous state. The compressor 32 also receives a small amount ofliquid from the bottom of the accumulator 62; this liquid lubricates thecompressor 32.

The cooling system 10 also includes two switches 64, 66, each of whichis in communication with the PCM 46. As described below, the switchesare pressure sensitive devices. Of course, a cooling system, such as thecooling system 10, may employ other types of pressure sensitive devices,such as pressure transducers. The first switch 64 is disposed betweenthe compressor outlet 36 and the orifice tube 58. Thus, it may bereferred to as a high pressure switch. Conversely, the switch 66 isdisposed between the front evaporator coil 18 and the compressor inlet34, and thus, may be referred to as a low pressure switch.

The high pressure switch 64 is configured to determine the pressure ofthe refrigerant in a conduit system 30, and to effect shutdown of thecompressor 32 when the refrigerant pressure gets above a predeterminedpressure. This helps to ensure that the pressure of the refrigerant in aconduit system 30 will never get high enough to damage any of thecomponents of the cooling system 10, or to vent refrigerant into theatmosphere. The compressor outlet 36 includes a pressure relief valve(not shown) that allows refrigerant to be released when the pressurereaches a predetermined level.

The high pressure switch 64 performs a second function, and thus, may bereferred to as a dual function switch. In addition to effecting ashutdown of the compressor 32 when the refrigerant pressure gets toohigh, the high pressure switch 64 also signals the PCM 46 to operate thefans 50, 52. This provides a mechanism to reduce the refrigerantpressure prior to the pressure reaching the level where the compressor32 is shut down. When the switch 64 detects that the refrigerantpressure needs to be reduced, it will signal the PCM 46 to start thefans 50, 52 if they are off, and to increase their speed if they arealready running. This provides additional cooling for the refrigerant asit flows through the third heat exchanger 48, which may effect apressure reduction so that a shutdown of the compressor 32 is notrequired.

Similarly, the low pressure switch 66 is configured to determine thepressure of the refrigerant in the conduit system 30 and to effect ashut down of the compressor 32 when the refrigerant pressure is below apredetermined pressure. This helps to ensure that enough refrigerant isflowing into the compressor 32 to cool and lubricate the internalmechanisms of the compressor 32. The switches 64, 66 are connected tothe compressor 32 such that they directly effect shutdown of thecompressor 32 when the pressure of the refrigerant and the conduitsystem 32 gets too high or too low. Alternatively, switches, such as theswitches 64, 66, can be configured to communicate with the PCM 46. Insuch an embodiment the switches 64, 66 would signal the PCM 46 when therefrigerant pressure is too high or too low, and the PCM 46 would effecta shutdown of the compressor 32.

As discussed above, the thermistors 42, 44 communicate with the PCM 46,and are configured to provide signals to the PCM 46 indicative of theair temperature exiting the front and rear evaporator coils 18, 20,respectively. The PCM 46 is configured to effect a stoppage ofrefrigerant flow to the front evaporator coil 18 when the firsttemperature, as measured by the thermistor 42, is below a predeterminedtemperature. Similarly, the PCM 46 is configured to effect a stoppage ofrefrigerant flow to the rear evaporator coil 20 when the secondtemperature, as measured by the thermistor 44, is below thepredetermined temperature. This helps to prevent damage to theevaporator coils 18, 20, and helps to ensure that they do not get socold that ice forms on the coils, thereby reducing the efficiency of thecooling system 10.

Similarly, the PCM 46 is configured to effect a stoppage of refrigerantflow to either evaporator coil 18, 20 when the cooling of the respectivevehicle space is not required. The PCM 46 can effect a stoppage ofrefrigerant flow in a number of different ways. For example, the PCM 46can close the valves 38, 40 individually, thereby stopping refrigerantflow to only one evaporator coil. The PCM 46 can also shutdown thecompressor 32, thereby stopping refrigerant flow to both evaporatorcoils 18, 20. Alternatively, the PCM 46 can close either or both valves38, 40, and simultaneously shutdown the compressor 32.

As shown in FIG. 1, the rear evaporator coil 20 can be used to providecool air to a battery, such as the battery 16. The air flowing througheither evaporator coil 18, 20 can be fresh air, or recirculated. Anumber of configurations can be used to provide fresh or recirculatedair to a battery compartment, such as the battery compartment 14. Anexample of such a system is described in copending U.S. PatentApplication Publication No. 2005/0056472, entitled “Cooling System For AVehicle Battery,” filed on Sep. 12, 2003, and incorporated herein byreference.

FIG. 4 shows one configuration of how the evaporator coil 20 can be usedto provide air to cool the battery 16. As seen in FIG. 4, the rearevaporator coil 20 is disposed within the rear duct system 28. The rearduct system 28 includes an air intake 68 which communicates with avehicle air intake 70. The vehicle air intake 70 is attached to a rearquarter window 72 to provide an inlet for ambient air from outside thevehicle into the duct system 28. Having a fresh air intake for a batterycooling system, particularly one that is located high-up on a vehicle,may have a number of benefits. Such an air intake is described in U.S.Patent Application Publication No. 2005/0059338, entitled “Fresh AirIntake For A Vehicle,” filed on Sept. 12, 2003, and incorporated hereinby reference. As seen in FIG. 4, the duct system 28 provides an air flowpath from outside the vehicle through the evaporator coil 20 to thebattery 16, as indicated by the direction arrow. The duct system 28 alsoprovides an air flow path back from the battery 16, such that the airmay be recirculated through the evaporator coil 20, or exhausted outsidethe vehicle through an air extractor 74.

As seen in FIG. 5, the configuration of the rear evaporator coil 20 andthe rear duct system 28 may be conveniently located in a vehicle 76 soas to minimize the amount of space taken from the passenger compartment12. For example, a first portion 78 of the rear duct system 28 may bedisposed along one side 80 of the vehicle 76. A second portion 82 of therear duct system 28 may be disposed beneath a load floor 84 so as tocome into close proximity to the battery 16, while not taking up spacein the vehicle passenger compartment 12.

While the best mode for carrying out the invention has been described indetail, those familiar with the art to which this invention relates willrecognize various alternative designs and embodiments for practicing theinvention as defined by the following claims.

1. A cooling system for a vehicle having first and second spaces to becooled, the cooling system including first and second heat exchangersfor respectively cooling air flowing into the first and second vehiclespaces, and a conduit system in communication with the first and secondheat exchangers and configured to provide a fluid flow path to and fromthe heat exchangers, the cooling system further including a pumpselectively operable for moving fluid through the conduit system, andfirst and second valves in communication with the conduit system, thecooling system comprising: a first sensor configured to measure a firsttemperature, and to output a signal related to the first temperature,the first temperature being indicative of the temperature of air exitingthe first heat exchanger; a second sensor configured to measure a secondtemperature, and to output a signal related to the second temperature,the second temperature being indicative of the temperature of airexiting the second heat exchanger; and a controller in communicationwith the first and second sensors, and with at least one of the pump andthe first and second valves, the controller being configured to effect astoppage of fluid flow to the first heat exchanger when the firsttemperature is below a predetermined temperature, and to effect astoppage of fluid flow to the second heat exchanger when the secondtemperature is below the predetermined temperature, and wherein thefirst vehicle space is a passenger compartment, and the second vehiclespace is a battery compartment.
 2. The cooling system of claim 1,wherein the controller is configured to effect a stoppage of fluid flowto the first and second heat exchangers by stopping operation of thepump.
 3. The cooling system of claim 1, wherein the controller is incommunication with the first and second valves, and wherein thecontroller is configured to effect a stoppage of fluid flow to the firstheat exchanger by closing the first valve, and to effect a stoppage offluid flow to the second heat exchanger by closing the second valve. 4.The cooling system of claim 1, further comprising a reservoircommunicating with the conduit system, and configured to temporarilystore at least some fluid flowing in the conduit system, and tofacilitate separation of liquid and vapor in the stored fluid.
 5. Thecooling system of claim 1, wherein the pump includes one of a compressorhaving a clutch, a variable displacement compressor, and a high-voltage,integrated electric motor driven compressor.
 6. The cooling system ofclaim 1, further comprising a third heat exchanger communicating withthe conduit system and disposed between the pump outlet and the firstand second heat exchangers, the third heat exchanger being configured tocool fluid flowing in the conduit system.
 7. The cooling system of claim6, further comprising first and second throttling devices, each of thethrottling devices communicating with the conduit system, and configuredto effect a reduction in pressure of fluid flowing through the conduitsystem, the first throttling device being disposed between the firstvalve and the first heat exchanger, the second throttling device beingdisposed between the second valve and the second heat exchanger.
 8. Thecooling system of claim 7, the pump including an inlet and an outlet,the cooling system further comprising a pressure sensitive devicedisposed between the pump outlet and one of the throttling devices, thepressure sensitive device being configured to determine a fluid pressurein the conduit system, and to effect shutdown of the pump when thedetermined fluid pressure is above a predetermined pressure.
 9. Thecooling system of claim 8, further comprising at least one fan disposedin relation to the third heat exchanger for moving air through the thirdheat exchanger, and wherein the pressure sensitive device is furtherconfigured to effect selective operation of the fan in response to thedetermined fluid pressure in the conduit system.
 10. The cooling systemof claim 1, the vehicle having a battery disposed within the batterycompartment, the cooling system further comprising a duct system havingat least a portion of the second heat exchanger disposed therein, theduct system being configured to selectively provide fluid communicationbetween the battery and an ambient environment outside the vehicle. 11.The cooling system of claim 10, further comprising a fan cooperatingwith the duct system for moving air through at least a portion of theduct system and across the battery.
 12. A vehicle having a passengercompartment and a battery, the vehicle comprising: a cooling systemincluding, a) first and second heat exchangers, the first heat exchangerbeing disposed in relation to the passenger compartment for selectivelycooling air flowing into the passenger compartment, the second heatexchanger being disposed in relation to the battery for selectivelycooling air flowing across the battery, b) a conduit system incommunication with the first and second heat exchangers, and configuredto provide a fluid flow path to and from the heat exchangers, c) a pumpselectively operable for moving fluid through the conduit system, d)first and second valves, each of the valves communicating with theconduit system, the first valve being configured to selectively inhibitfluid flow to the first heat exchanger, the second valve beingconfigured to selectively inhibit fluid flow to the second heatexchanger, e) first and second sensors, the first sensor beingconfigured to measure a first temperature indicative of the temperatureof air exiting the first heat exchanger, and further configured tooutput a signal related to the first temperature, the second sensorbeing configured to measure a second temperature indicative of thetemperature of air exiting the second heat exchanger, and furtherconfigured to output a signal related to the second temperature, and f)a controller in communication with the first and second sensors and atleast one of the pump and the first and second valves, the controllerbeing configured to effect a stoppage of fluid flow to the first heatexchanger when the first temperature is below a predeterminedtemperature, and to effect a stoppage of fluid flow to the second heatexchanger when the second temperature is below the predeterminedtemperature.
 13. The vehicle of claim 12, wherein the controller isconfigured to effect a stoppage of fluid flow to the first and secondheat exchangers by stopping operation of the pump.
 14. The vehicle ofclaim 12, wherein the controller is configured to effect a stoppage offluid flow to the first heat exchanger by closing the first valve, andto effect a stoppage of fluid flow to the second heat exchanger byclosing the second valve.
 15. The vehicle of claim 12, wherein thecooling system further comprises a duct system having at least a portionof the second heat exchanger disposed therein, the duct system beingconfigured to selectively provide fluid communication between thebattery and an ambient environment outside the vehicle.